Abstract: The present invention relates to a magnetic mono-component toner composition, and more particularly to a mono-component toner composition that comprises magnetic toner particle comprising a binder resin, a magnetic component, and a charge control agent; a hydrophobic treated silica having a specific surface area of 20 to 80 m2/g; a hydrophobic treated silica having a specific surface area of 130 to 230 m2/g; and a metal oxide fine powder. A magnetic mono-component toner composition of the present invention has such good flowability that it provides smooth toner supply even when the developing roller surface has been worn due to long time use, and it has such excellent uniform chargeability that it prevents image deterioration (“wave” patterns of toner may form on developing roller, that is, magnetic sleeve) by forming an uniform toner layer on the developing roller.

Abstract: The present invention provides a toner for electrostatic charge development comprising an amorphous polyester resin, a releasing agent, and magnetic metal particles covered with a resin the main component of which is a crystalline polyester resin.

Abstract: Magnetic toner compositions, conductive developer compositions, and methods for producing images in a hybrid jumping development system, more specifically, in a magnetic ink character recognition system, are disclosed. The developer compositions contain coated magnetic toner particles and coated carrier particles. The toner compositions include a resin, colorant, wax, magnetic component, and surface additives of coated silica, titania, and zinc stearate.

Abstract: In a magnetic toner having toner particles containing at least a binder resin and a magnetic material, the binder resin is chiefly composed of a resin having a polyester unit synthesized using as a catalyst a tin compound represented by the following Formula (1), and the magnetic material has a number-average particle diameter of form 0.1 ?m to 0.3 ?m: (RCOO)2Sn??Formula (1) wherein R represents an alkyl group having 5 to 15 carbon atoms. This magnetic toner can attain a stable image density without dependence on environment and enables formation of high-grade images over a long period of time without causing scratches of latent image bearing members.

Abstract: A toner for developing a latent electrostatic image to a toner image, including a binder resin, and a magnetic material which is blackened by coating the surface of a magnetic powder with a coloring agent, the magnetic material being in an amount of 10 wt.% to 40 wt.% of the entire weight of the toner, a method of forming an image, using a two-component developer containing the toner, an image formation apparatus using the two-component developer, and a toner container containing therein the toner, and an image formation apparatus equipped with the toner container are proposed.

Abstract: A method for making ferrite powder may include providing ferrite feed materials in a form of particles having different sizes and irregular shapes, and exposing the ferrite feed materials to a plasma to provide a more spherical shape to irregularly shaped particles to thereby make the ferrite powder. An apparatus for making ferrite powder may include a feeder for ferrite feed materials and a plasma generator for exposing the ferrite feed materials to a plasma.

Abstract: Development systems and methods for developing using magnetic toner are disclosed. The present invention further discloses developers used in development systems as well as the toner used in developer for magnetic ink character recognition printing. With respect to the development system, a development system is disclosed which includes a supply of dry developer mixture which contains magnetic toner particles and hard magnetic carrier particles. The development system further includes a non-magnetic, cylindrical shell for transporting the developer between the supply and the development zone, wherein the shell can be rotatable or stationary. A rotating magnetic core of a pre-selected magnetic field strength and means for rotating at least the magnetic core to provide for the transport of the toner particles from the shell to an electrostatic image also provided as part of the development system.

Abstract: Development systems and methods for developing using chemically prepared toners are disclosed. The present invention further discloses developers used in development systems. The use of chemically prepared toners with hard magnetic carrier particles with a non-magnetic, cylindrical shell for transporting developers provides excellent benefits with respect to image quality by reducing granularity and by providing a typically constant, stable developer life as shown by the consistent level of charge to mass over time during operation.

Abstract: A toner comprises toner particles comprising at least a binder resin, a colorant, and a sulfur-containing resin, in which the toner particles comprise the sulfur-containing resin so as to satisfy a relation of; 0.50?IS/TS?0.95 where TS denotes a content of sulfur in the toner particles, and IS denotes a content of sulfur in isopropyl alcohol insoluble components of the toner particles, whereby it is possible to obtain a high quality image having an excellent developing resistance regardless of the surrounding conditions and a uniform charge amount distribution regardless of processing speed.

Abstract: The toner for electrostatic charged image development of the present invention is characterized in that it contains at least a binder resin, a mold releasing agent and magnetic metal particles, and the solubility of the magnetic metal particles in a 1 mol/l aqueous HNO3 solution at 50° C. is 500 mg/g·l or less.

Abstract: A toner showing a high transferability and suitable for use in cleanerless image forming system is formed of toner particles comprising at least a binder resin and magnetic iron oxide. The toner is characterized by a specific circularity distribution relative to its weight-average particle size and a controlled degree of surface-exposed magnetic iron oxide providing an extract solution with hydrochloric acid showing an absorbance of 1.0-2.5 at a wavelength of 340 nm. The toner is suitably produced by a production system including a rotary mechanical pulverizer and a one-pass surface treatment apparatus for continuously applying a mechanical impact force to pulverized toner particles therein.

Abstract: A developing device including a developer containing magnetic toner grains and includes a main pole for development disposed in a sleeve. Flux density generated by the magnetic pole in a direction normal to the surface of the sleeve outside of the surface has an attenuation ratio of 50% or above. The toner grains have a weight mean grain size of 6.0 ?m to 8.0 ?m while the toner grains having grain sizes of 5 ?m and below occupy 40% to 80% of the entire developer. The toner grains have magnetization strength of 10 emu/g to 25 emu/g in a magnetic field of 5 kOe or magnetization strength of 7 emu/g to 20 emu/g in a magnetic field of 1 kOe. The toner grains reduce toner scattering and image defects despite that they are magnetic, thereby implementing ultrahigh resolution.

Abstract: A toner, such as an electrostatic latent image developing toner and a MICR toner, has an even charge distribution, and exhibits balanced charging characteristics without decreases in frictional electrification or increases in charge, as well as superior fluidity, environmental independence, and durability. This is achieved by treating toner particles, which include binder resin and magnetic particles, with an external additive particle that is one of: a combination of rutile-type titanium oxide and anatase-type titanium oxide; and rutile-type titanium oxide that falls in a range of 5 to 10% by volume when a total volume of the toner is regarded as being 100%.

Abstract: The present invention relates to a magnetic toner composition, and more particularly to a magnetic toner composition having an improved chargeability and excellent uniform chargeability, and that is capable of reducing a difference in electrostatic charge between a toner remaining in a cartridge or in a developing unit and that of a newly supplied toner. A magnetic toner composition of the present invention comprises magnetic toner particulate comprising a binder resin and a magnetic substance, a conductive fine powder having a specific surface area of 30 to 300 m2/g, a hydrophobic silica having a specific surface area of 100 to 240 m2/g, and an inorganic fine powder having an average diameter of 0.1 to 4.O&mgr;m.

Abstract: In a magnetic toner having toner particles containing at least a binder resin and a magnetic material, the binder resin is chiefly composed of a resin having a polyester unit synthesized using as a catalyst a tin compound represented by the following Formula (1), and the magnetic material has a number-average particle diameter of form 0.1 &mgr;m to 0.

Abstract: Development systems and methods for developing using magnetic toner are disclosed. The present invention further discloses developers used in development systems as well as the toner used in developer for magnetic ink character recognition printing. With respect to the development system, a development system is disclosed which includes a supply of dry developer mixture which contains magnetic toner particles and hard magnetic carrier particles. The development system further includes a non-magnetic, cylindrical shell for transporting the developer between the supply and the development zone, wherein the shell can be rotatable or stationary. A rotating magnetic core of a pre-selected magnetic field strength and means for rotating at least the magnetic core to provide for the transport of the toner particles from the shell to an electrostatic image also provided as part of the development system.

Abstract: This invention relates to a process for producing magnetite particles having a coercivity of 6.366 kA/m to 10.345 kA/m (=80 to 130 Oe) and an octahedral particle shape, comprising heating an alkaline component and an iron(II) component in the form of an aqueous solution to a temperature of 50° C. to 100° C., whereby the molar ratio of iron(II) component to one equivalent of alkaline component is 0.38 to 0.45, and treating the suspension with an oxidizing agent at a rate of oxidation of 20 to 50 mol. % Fe(II)/h until the iron compound has an Fe(III) content of more than 65 mol. %, and then again adding an Fe(II) component in the form of an aqueous solution at a molar ratio of Fe(II) to one equivalent of total alkaline component used is 0.47 to 0.49, and treating the suspension with an oxidizing agent, at a rate of oxidation is 20 to 50 mol. % Fe(II)/h until the iron compound has an Fe(III) content of more than 65 mol.

Abstract: The invention relates to a toner containing low-silicon magnetite particles.

Abstract: The toner for electrostatic charged image development of the present invention is characterized in that it contains at least a binder resin, a mold releasing agent and magnetic metal particles, and the solubility of the magnetic metal particles in a 1 mol/l aqueous HNO3 solution at 50° C. is 500 mg/g·l or less.

Abstract: Development systems and methods for developing using toner are disclosed. The present invention further discloses developers used in development systems. With respect to the development system, a development system is disclosed which includes a supply of dry developer mixture which contains toner particles and hard magnetic carrier particles. The development system further includes a non-magnetic, cylindrical shell for transporting the developer between the supply and the development zone, wherein the shell can be rotatable or stationary. A rotating magnetic core of a pre-selected magnetic field strength and means for rotating at least the magnetic core to provide for the transport of the toner particles from the shell to an electrostatic image also provided as part of the development system. The development system of the present invention further includes a fuser roll which is coated with a silicone rubber or other low surface energy elastomer or resin.

Abstract: A two component developer comprising a magnetic toner containing a binder resin and a magnetic particle, and a magnetic carrier containing a magnetic particle, wherein the magnetic toner has an average particle diameter of 4.0 to 10.0 &mgr;m, and contains 5 to 80 No. % of toner particles having particle diameter of 5 &mgr;m or less, and exhibits magnetization of 10 to 25 emu/g under magnetic field of 5 kiloersteds.

Abstract: A toner comprising a resin binder comprising a crystalline resin having a ratio of a softening point to a maximal peak temperature of heat of fusion of 0.6 or more and less than 1.1, and an amorphous hybrid resin having a ratio of a softening point to a maximal peak temperature of heat of fusion of from 1.1 to 4.0; and a colorant, wherein the amorphous hybrid resin comprises two polymerization resin components each having an independent reaction path, said two polymerization resin components being partially chemically bonded to each other, wherein at least one polymerization resin component is the same as that of the crystalline resin, and wherein a weight ratio of the crystalline resin to the amorphous hybrid resin (crystalline resin/amorphous hybrid resin) is from 1/99 to 50/50. The toner can be used for developing electrostatic latent images formed in electrophotography, electrostatic recording method, electrostatic printing, and the like.

Abstract: Development systems and methods for developing using magnetic toner are disclosed. The present invention further discloses developers used in development systems as well as the toner used in developer for magnetic ink character recognition printing. With respect to the development system, a development system is disclosed which includes a supply of dry developer mixture which contains magnetic toner particles and hard magnetic carrier particles. The development system further includes a non-magnetic, cylindrical shell for transporting the developer between the supply and the development zone, wherein the shell can be rotatable or stationary. A rotating magnetic core of a pre-selected magnetic field strength and means for rotating at least the magnetic core to provide for the transport of the toner particles from the shell to an electrostatic image also provided as part of the development system.

Abstract: The present invention provides a toner for MICR suitable for use in a printer for a non-magnetic monocomponent developing system, which does not produce scratches on a developing sleeve when used in the printer for the non-magnetic monocomponent developing system and has a resistance against sliding friction with a magnetic head, and also causes no reading errors because of a proper signal strength and imparts satisfactory image characteristics (for example, with respect to image density and fogging). The toner comprises a binder resin, a magnetic material and a wax, and has a BET specific surface area within a range from 0.70 to 1.00 m2/g.

Abstract: A toner of the present invention comprises at least a binder resin comprising as a main component a polyester resin, a wax, and a colorant, in which in case of measuring a wettability of the toner with respect to a mixed solvent of methanol and water in terms of an optical transimittance at an optical wavelength of 780 nm, a methanol concentration of the mixed solvent is in a range of 45 to 65% by volume when an optical transmittance is 80% and 10%, respectively; a melt index (MI) is of 0.1 to 10 g/10 min at a temperature of 125° C.

Abstract: An electrostatic developing toner which can effectively suppress image fogging*1 by setting a ratio (d/D) of the average particle diameter D of the toner and the average particle diameter d of iron oxide particles contained in the toner as a colorant to within a predetermined range, and by setting the value of a ratio (&sgr;r/&sgr;s) between the residual magnetization rr and saturation magnetization &sgr;s of the iron oxide particles to a predetermined value or less, is provided. The value of the ratio (d/D) of the average particle diameter D of the toner and the average particle diameter d of iron oxide particles contained in the toner as a colorant is set to within the range of 0.01-0.03, and the value of the ratio (&sgr;r/&sgr;s) between the residual magnetization &sgr;r and saturation magnetization &sgr;s of the iron oxide particles is set to 0.3 or less.

Abstract: An electrophotographic toner for visualizing an electrostatic latent image formed by an electrophotographic process, an electrostatic printing process, an electrostatic recording process, etc., which is produced in consideration of the environment and safety. The electrophotographic toner includes a fixing resin and a colorant. The electrophotographic toner is a black toner using a titanium compound containing no carbon black as the colorant. The electrophotographic toner may be an electrophotographic two-component black toner using magnetic iron oxide containing no carbon black as the colorant.

Abstract: A toner contains at least a bonding resin and a coloring agent, and has a weight mean particle size from 5 &mgr;m to 12 &mgr;m; not less than 90% by number of particles not less than 3 &mgr;m have a circularity “a” not less than 0.900; a cut ratio Z and a weight mean size X of the toner are related as: cut ratio Z≦5.3×X; and a relationship of particles Y having a circularity of not less than 0.950 and a weight mean size X is Y≧e5.51×X−0.645 where X is 5 to 12 &mgr;m.

Abstract: An electrophotographic toner containing: a fixing resin, a colorant, and wax. The wax at least contains hydrocarbon wax having a number-average molecular weight of not higher than 600, and polyethylene wax having a number-average molecular weight of not higher than 600, a melting viscosity of lower than 15 mPa·s at 140° C. and a crystallinity of lower than 95%. A ratio of the hydrocarbon wax to the polyethylene wax is in a range of from 1:10 to 2:1. A maximum of absorption peaks in a heat-up time absorption calorie curve in a DSC curve of the toner measured by a differential scanning calorimeter is at a temperature not higher than 75° C. An onset temperature in absorption of heat is not higher than 65° C.

Abstract: A toner comprises toner particles comprising at least a binder resin, a colorant, and a sulfur-containing resin, in which the toner particles comprise the sulfur-containing resin so as to satisfy a relation of; 0.50≦IS/TS≦0.95 where TS denotes a content of sulfur in the toner particles, and IS denotes a content of sulfur in isopropyl alcohol insoluble components of the toner particles, whereby it is possible to obtain a high quality image having an excellent developing resistance regardless of the surrounding conditions and a uniform charge amount distribution regardless of processing speed.

Abstract: A magnetic toner for MICR printers is provided with a binder resin, magnetic powder, and metal oxide particles which are in the outer surface of each toner base particle made from the binder resin and the magnetic powder, the metal oxide particles having a volume resistivity of 1×105 to 1×1011 &OHgr;·cm. A developer containing this MICR toner makes it possible to provide superior image density and reading precision, even after 150,000 to 300,000 sheets of A-4 paper have been continuously printed.

Abstract: A magnetic toner includes a magnetic toner particle containing a binding resin and a magnetic material. The magnetic material includes a magnetic iron oxide containing 0.10% to 4.00% by weight of an element &agr; belonging to the third period to the seventh period with an atomic number of 11 to 103 and having an electronegativity of 1.0 to 2.5. The solubility S1 of &agr; in the magnetic material at an iron solubility of 0% to 20% is from 10% to less than 44% and the solubility S2 of &agr; at an iron solubility of 80% to 100% is from 5% to less than 30%. The magnetic material contains at least 60% by number of multinuclear magnetic iron oxide particles or at least 60% by number of polyhedral magnetic iron oxide particles having faces at ridgeline portions of hexahedron and/or octahedron multinuclear magnetic iron oxide particles.

Abstract: A magnetic toner exhibiting stable performances under various environmental conditions is formed of toner particles each comprising at least a binder resin and iron oxide dispersed therein. Relative to the dry specific gravity (A) of the magnetic toner, the magnetic toner is characterized by a specific gravity distribution of toner particle fractions obtainable through wet sedimentation and including: at most 15 wt. % of a fraction having a specific gravity of above (A)×1.000 and at most (A)×1.025, 0.1-20 wt. % of a fraction having a specific gravity of above (A)×0.975 and at most (A)×1.000, at least 30 wt. % of a fraction having a specific gravity of above (A)×0.950 and at most (A)×0.975, 0.1-20 wt. % of a fraction having a specific gravity of above (A)×0.925 and at most (A)×0.950, and at most 15 wt. % of a fraction having a specific gravity of above (A)×0.900 and at most (A)×0.925.

Abstract: A developing apparatus includes a first developing system for developing a latent image formed on an image bearing member with a first developer including magnetic toner. The first developing system includes a first developer carrying member for carrying and feeding the first developer to the image bearing member and a first magnetic field generating device disposed in the first developer carrying member. The developing apparatus further includes a second developing system develops a latent image formed on the image bearing member with a second developer including a magnetic carrier and non-magnetic toner while the developer contacts the image bearing member. The second developing system includes a second developer carrying member for carrying and feeding the developer to the image bearing member and a second magnetic field generating device disposed in the second developer carrying member. A magnetization intensity M&sgr; (Am2/kg) of the magnetic toner in an external magnetic field of 795.

Abstract: A magnetic toner is formed of magnetic toner particles each comprising a binder resin, an iron oxide, a sulfur-containing polymer, and inorganic fine powder blended with the magnetic toner particles, the toner having a weight-average particle size (D4) of 3-10 &mgr;m, and either (a) an average circularity of at least 0.970, and a magnetization of 10-50 Am2/kg (emu/g) at a magnetic field of 79.6 kA/m (1000 oersted), or (b) toner particles which retain carbon in an amount of A and iron in an amount of B at surfaces thereof, satisfying: B/A<0.001, and containing at least 50% by number of magnetic toner particles of D/C≦0.02, wherein C represents a particle projection area-equivalent circle diameter and D represents a minimum distance between a surface of the magnetic toner particle and iron oxide particles contained therein.

Abstract: Black magnetic toner comprising: a binder resin, and black magnetic composite particles comprising: magnetic iron oxide particles having an average particle diameter of 0.055 to 0.95 &mgr;m; a coating layer formed on the surface of said magnetic iron oxide particles, comprising at least one organosilicon compound selected from the group consisting of: (1) organosilane compounds obtainable from alkoxysilane compounds, (2) polysiloxanes or modified polysiloxanes, and (3) fluoroalkyl organosilane compounds obtainable from fluoroalkylsilane compounds; and a carbon black coat formed on said coating layer comprising said organosilicon compound, in an amount of 1 to 25 parts by weight based on 100 parts by weight of said magnetic iron oxide particles. Such a black magnetic toner can be free from being deteriorated in electric resistance due to the existence of the carbon black coat, and as a result, is suitable as a high-resistance or insulated magnetic toner.

Abstract: Development systems and methods for developing using magnetic toner are disclosed. The present invention further discloses developers used in development systems as well as the toner used in developer for magnetic ink character recognition printing. With respect to the development system, a development system is disclosed which includes a supply of dry developer mixture which contains magnetic toner particles and hard magnetic carrier particles. The development system further includes a non-magnetic, cylindrical shell for transporting the developer between the supply and the development zone, wherein the shell can be rotatable or stationary. A rotating magnetic core of a pre-selected magnetic field strength and means for rotating at least the magnetic core to provide for the transport of the toner particles from the shell to an electrostatic image also provided as part of the development system.

Abstract: A magnetic toner is formed of magnetic toner particles each comprising at least a binder resin and a magnetic iron oxide. The magnetic toner is provided with improved developing performances by realizing an appropriate surface-exposure state of the magnetic iron oxide, which is represented by a wettability characteristic in methanol/water mixture liquids of the magnetic toner such that it shows a transmittance of 80% for light at a wavelength of 780 nm at a methanol concentration in a range of 65-75% and a transmittance of 20% at a methanol concentration in a range of 66-76%.

Abstract: A multi-layered toner comprises a core containing a first binder resin, and a covering layer containing a second binder resin having an acid value differing from that of the first binder resin. A magnetic powder is contained in at least one of the core and the covering layer.

Abstract: Development systems and methods for developing using magnetic toner are disclosed. The present invention further discloses developers used in development systems as well as the toner used in developer for magnetic ink character recognition printing. With respect to the development system, a development system is disclosed which includes a supply of dry developer mixture which contains magnetic toner particles and hard magnetic carrier particles. The development system further includes a non-magnetic, cylindrical shell for transporting the developer between the supply and the development zone, wherein the shell can be rotatable or stationary. A rotating magnetic core of a pre-selected magnetic field strength and means for rotating at least the magnetic core to provide for the transport of the toner particles from the shell to an electrostatic image also provided as part of the development system.

Abstract: A two-component developer includes at least a magnetic toner and a magnetic carrier. The magnetic toner has magnetic particles coated with a carbon black layer. The magnetic toner adheres to the magnetic carrier due to the magnetic interaction.

Abstract: A toner comprising a resin binder comprising a crystalline resin having a ratio of a softening point to a maximal peak temperature of heat of fusion of 0.6 or more and less than 1.1, and an amorphous hybrid resin having a ratio of a softening point to a maximal peak temperature of heat of fusion of from 1.1 to 4.0; and a colorant, wherein the amorphous hybrid resin comprises two polymerization resin components each having an independent reaction path, said two polymerization resin components being partially chemically bonded to each other, wherein at least one polymerization resin component is the same as that of the crystalline resin, and wherein a weight ratio of the crystalline resin to the amorphous hybrid resin (crystalline resin/amorphous hybrid resin) is from 1/99 to 50/50. The toner can be used for developing electrostatic latent images formed in electrophotography, electrostatic recording method, electrostatic printing, and the like.

Abstract: A magnetic toner with a negative polarity for developing latent electrostatic images is made of toner particles, each toner particle containing a binder resin, a magnetic powder, and a charge control agent, the surface of the magnetic toner satisfying the relationship of 2×10−7≦C/Sw≦10×10−7, provided C≦8×10−3, wherein C is an amount (g/g) of the charge control agent dissolved in a solvent comprising water and methanol, and Sw is a specific surface area (cm2/cm3) of the toner particles determined from a weight-average particle diameter of the toner particles. An image forming apparatus has an electrostatic image bearing member, and a unit for developing the electrostatic image with the above magnetic toner, the unit having a developer holding member provided with a magnet, and a developer container.

Abstract: Black magnetic toner comprising: a binder resin; and black magnetic composite particles having an average particle diameter of 0.06 to 1.0 &mgr;m comprising: magnetic iron oxide particles, a coating layer formed on the surface of the magnetic iron oxide particles, comprising at least one organosilicon compound selected from the group consisting of: (1) organosilane compounds obtainable from alkoxysilane compounds, and (2) polysiloxanes or modified polysiloxanes, and a single carbon black coat formed on the coating layer comprising the organosilicon compound, in an amount of 26 to 55 parts by weight based on 100 parts by weight of the magnetic iron oxide particles.

Abstract: A two component developer comprising a magnetic toner containing a binder resin and a magnetic particle, and a magnetic carrier containing a magnetic particle, wherein the magnetic toner has an average particle diameter of 4.0 to 10.0 &mgr;m, and contains 5 to 80 No. % of toner particles having particle diameter of 5 &mgr;m or less, and exhibits magnetization of 10 to 25 emu/g under magnetic field of 5 kiloersteds.

Abstract: Black magnetic toner comprising:

Abstract: A magnetic toner exhibiting stable performances under various environmental conditions is formed of toner particles each comprising at least a binder resin and iron oxide dispersed therein. Relative to the dry specific gravity (A) of the magnetic toner, the magnetic toner is characterized by a specific gravity distribution of toner particle fractions obtainable through wet sedimentation and including: at most 15 wt. % of a fraction having a specific gravity of above (A)×1.000 and at most (A)×1.025, 0.1-20 wt. % of a fraction having a specific gravity of above (A)×0.975 and at most (A)×1.000, at least 30 wt. % of a fraction having a specific gravity of above (A)×0.950 and at most (A)×0.975, 0.1-20 wt. % of a fraction having a specific gravity of above (A)×0.925 and at most (A)×0.950, and at most 15 wt. % of a fraction having a specific gravity of above (A)×0.900 and at most (A)×0.925.

Abstract: A toner for developing electrostatic images is comprised of a binder resin and a wax. The binder resin contains as a primary component a polyester resin having a soft segment. The wax has, in its endothermic peaks at the time of temperature rise and exothermic peaks at the time of temperature drop in the DSC curve measured using a differential scanning calorimeter; (i) an endothermic onset temperature within the range of from 50° C. to 110° C.; (ii) at least one endothermic peak P1 within the range of from 70° C. to 130° C. at the time of temperature rise; and (iii) a maximum exothermic peak at the time of temperature drop, within the range of plus-minus 9° C. of the endothermic peak P1.

Abstract: A magnetic toner contains, as a magnetic powder, magnetic iron oxide having an octahedral particle shape and an average particle diameter of 0.21 &mgr;m or larger and containing 18% or more by weight of FeO. The magnetic toner is so prepared as to have a bulk density A (g/cm3) and a magnetic powder content B (% by weight) that fulfill the formulae 0.8≦A/B×100≦1.6 and 35≦B≦50. This alleviates the reddishness of images produced with the magnetic toner, and alleviates the disturbance of a thin toner layer on a developing sleeve and thus the fogging resulting therefrom.

Abstract: A toner contains at least a bonding resin and a coloring agent, and has the following characteristics (i) to (iv):